The present invention relates in general to bonding outer leads to inner leads and, more particularly, to an apparatus for automatically and accurately removing sets of inner leads and a die from a film carrier, moving the set into proper alignment with the outer leads and effecting a bond between the inner and outer leads.
To increase production and yield, the semi-conductor industry has sought to automate the processes for assembling integrated circuits and other semiconductor devices. These efforts have lead to the development of the film-carrier as a replacement for the widely used wire-bonding techniques. A film-carrier consists of a strip of plastic film having sprocket holes at its edges and carries the inner lead frames. The leads in each lead frame are simultaneously bonded to the bonding pads on the die by bonding apparatus. Sprocket holes along the sides of the film carrier function to provide a means to advance the film carrier after a die has been bonded to the leads. This allows the film carrier and dies to be taken up on a reel or the like for further processing.
The major advantage of the film-carrier technique over other bonding techniques is that it lends itself to full automation. The present invention is directed toward apparatus for automatically bonding film-carrier inner leads to outer leads. In particular, the present invention is concerned with apparatus for sequentially advancing inner lead frames mounted on a film carrier to a bonding site, sequentially advancing outer lead frames to the bonding site, removing a set of inner leads and the die bonded thereto from the film carrier and moving the set into a bonding position with the inner and outer leads properly aligned, and then effecting a bond between said leads. To accomplish this, the outer leads are sequentially fed to and accurately positioned at the bonding site. In a like manner, individual sets of inner leads and dies are sequentially advanced to the bonding site. A punch accurately removes a set of inner leads and associated die from the film carrier and moves it into proper alignment with the outer leads. Thereafter, a bonding tool bonds the inner leads to the outer leads such as by thermocompression bonding. Thereafter, the next outer lead frame and next set of inner leads and die are advanced to the bonding site. The foregoing is accomplished automatically, that is, without human intervention.